Polyamine additives for fuels and lubricants

ABSTRACT

The present invention relates to the use of polyamines having at least one terminal secondary or tertiary amine function as a detergent additive for fuels and lubricants; to additive concentrates comprising such polyamines; to fuels and lubricants additized with these polyamines and to processes for their preparation.

The present invention relates to the use of polyamines having at leastone terminal secondary or tertiary amine function as a detergentadditive for fuels and lubricants; to additive concentrates comprisingsuch polyamines; to fuels and lubricants additized with these polyaminesand to processes for their preparation.

PRIOR ART

During the operation of combustion engines, there may be formation ofundesired deposits in the region of the combustion chamber and of thefuel intake system. In the case of diesel fuels, carbon deposits are tobe observed in the region of the injection nozzles and holes and canimpair the optimal formation of a finely divided fuel mist indirection-injection high-performance systems such as common rail,pump-nozzle or pump-line-nozzle and thus lead to increased fuelconsumption and emissions. In order to minimize or entirely prevent thedisruptions associated with the occurrence of such deposits, detergentadditives are added to the fuels.

Examples of such detergent additives include in particularpolyalkenylsuccinimides. These find manifold use in fuels andlubricants, typically in combination with other additives; cf., forexample, EP-A-0264247, EP-A-0271937 and WO-A-98/42808.

For instance, WO-A-98/42808 describes the use of specific reactionproducts of a polyalkenyl derivative of a monoethylenically unsaturatedC₄-C₁₀-dicarboxylic acid with a polyamine having terminal primary aminegroups as a detergent additive for low-sulfur diesel fuels.

DE-A-101 23 553 discloses a process for preparingpolyalkenylsuccinimides in which PIBSA is, for example, reacted with anoligo- or polyamine in the presence of an alcohol. The oligo- orpolyamines used likewise have terminal primary amine groups.

WO 2004/024851 describes synergistically active additive mixtures forlubricants and fuels composed of an additive having detergent action anda partly or fully neutralized fatty acid. The detergent additivesspecified include compounds having a hydrophobic hydrocarbon radicalhaving an Mn of from 85 to 20 000 whose polar end group is selected frommoieties derived from carboxylic anhydrides and having hydroxyl and/oramino and/or amido and/or imido groups. Dicarboximides of polyalkylenepolyamines having terminal secondary or tertiary amine end groups in theend product were not investigated therein.

A disadvantage of the additives and the additive mixtures described inthe prior art is that relatively high dosages are required to achieve acleaning or keep-clean effect.

BRIEF DESCRIPTION OF THE INVENTION

It is therefore an object of the present invention to provide improveddetergent additives for fuel and lubricant compositions, especiallydiesel fuels, which are effective even at low dosages and especiallyeffectively reduce nozzle carbonization.

It has been found that, surprisingly, the above object is achieved byproviding linear polyamines having at least one terminal secondary ortertiary amine function as a detergent additive for fuels andlubricants.

The invention firstly provides the use of a compound of the generalformula I

R¹R²N((CH₂)_(x)NH)_(y)(CH₂)_(z)NR³R⁴  (I)

whereR¹, R², R³ and R⁴ are each independently H or C₁-C₁₀-alkyl but neitherR¹ and R² nor R³ and R⁴ are simultaneously H; or R1 and R² together withthe nitrogen atom to which they are bonded form a C₄-C₆-dicarboximidering which is substituted by at least one polyalkenyl radical R whichhas a number-average molecular weight Mn of from 100 to 2500, and whereR³ and R⁴ are preferably simultaneously C₁-C₁₀-alkyl;y is an integer from 1 to 100, for example from 1 to 50, from 1 to 20 orfrom 1 to 10, for example 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 andx and z are independently an integer from 2 to 12, for example from 2 to10, from 2 to 8, from 2 to 6 or 2, 3 or 4,as a detergent additive for fuels and lubricants. In particular its usefor diesel fuels and in that caseits use for the purpose of reducing thecarbonization of the nozzles in diesel engines should be mentioned. Forexample, the additives according to the present invention are suitablefor reducing the carbonization of the nozzles in diesel engines withdirect fuel injection, like those based on the “common rail”,“pump-nozzle” or “pump-line-nozzle” principles.

A “reduction of the carbonization of the nozzles” is understood to be apartial or complete reduction of the degree of the carbonization of thenozzles in comparison with the degree of carbonization occurring with afuel without additives (i.e. in the absence of a compound of formula Iin the fuel), as determined in a standardized test engine, in particularin accordance with the standardized test engine employed for thedetermination of air flow restriction described below.

A first preferred group of compounds comprises compounds of thefollowing general formula II

where x, y, z, R, R³ and R⁴ are each as defined above. Such compoundsare thus terminated by a secondary or tertiary amine function.Especially mentioned are compounds of formula II where R³ and R⁴ are thesame or different and are a C₁-C₁₀-, C₁-C₈-, C₁-C₆-, C₁-C₅- orC₁-C₄-alkyl group.

Embodiments of polyalkenyl radicals R which are preferred in accordancewith the invention are illustrated later in section C2). Especiallypreferably, R is a polyisobutenyl radical. The polyisobutenyl radicalhas in particular an Mn of from about 500 to 1000.

A second preferred group of compounds comprises compounds of the formulaI, wherein R¹, R², R³ and R⁴ are each independently H or C₁-C₁₀-alkylbut neither R¹ and R² nor R³ and R⁴ are simultaneously H, and x, y and zare each as defined above. Such compounds are thus terminated by twosecondary and/or tertiary amine functions.

Preference is given in particular to those compounds of the formula Iand II, wherein x and z are each independently an integer from 2, 3 or 4and y is 1, 2 or 3.

Particular preference is further given to those compounds of the formulaI and II wherein R³ and R⁴ are each independently H or C₁-C₈-, C₁-C₆-,C₁-C₅ or C₁-C₄-alkyl but R³ and R⁴ may not simultaneously each be H; orwherein R³ and R⁴ are simultaneously C₁-C₈-, C₁-C₆-, C₁-C₅ orC₁-C₄-alkyl. Preferably R³ and R⁴ have the same meaning.

Particular preference is also given to compounds of the formula Iwherein R¹, R², R³ and R⁴ are simultaneously each C₁-C₄-alkyl.

In another preferred embodiment, the reaction products or mixtures,partly purified if appropriate, obtained in the preparation of compoundsof the formula I are used.

It is possible in accordance with the invention to use, for example, areaction product comprising an imide compound of the formula I, forexample a compound of the formula II, the reaction product beingobtainable by reacting a cyclic C₄-C₆-dicarboxylic anhydride which issubstituted by at least one polyalkenyl radical R which has anumber-average molecular weight Mn of from 100 to 2500 with a polyamineof the formula III

H₂N((CH₂)_(x)NH)_(y)(CH₂)_(z)NR³R⁴  (III)

where x, y, z, R³ and R⁴ are each as defined above, if appropriatefollowed by a removal of volatile constituents of the reaction mixture.The reaction can be effected according to the disclosure of DE-A-101 23553.

The above-described detergent additives are used customarily incombination with at least one further conventional fuel or lubricantadditive which will be described more precisely later.

The additive of the formula I is added in an amount of about 1-200 mg/kgof fuel, more preferably in a dosage of from 1 to 100, from 1 to 50,from 1 to 30, from 2 to 20 or from 2 to 16 mg/kg of fuel.

The additive of the formula I is preferably added in an amount whichbrings about a maximum degree of carbonization of 80%, preferably of70%, for example from 0 to 65%, from 2 to 50% or from 5 to 40%,determined to CEC F23 A 01 (in an XUD9 test engine at 0.1 mm needlestroke) via the percentage air flow restriction.

The invention further provides fuel compositions comprising in amajority of a hydrocarbon fuel boiling in the range from 100 to 500° C.,for example from 150 to 400° C. or from 160 to 360° C., in particular amiddle distillate fuel, for example diesel fuel, an effective amount ofat least one detergent additive of the formula I as defined above.

The invention also provides lubricant compositions comprising in acustomary lubricant, at least an effective amount of at least onedetergent additive of the formula I as defined above.

The invention also relates to additive concentrates comprising at leastone detergent additive of the formula I as defined above in combinationwith at least one further customary fuel or lubricant additive. Theinventive additive is present in the concentrates preferably in anamount of from 0.1 to 80% by weight, more preferably from 1 to 70% byweight and in particular from 20 to 60% by weight, based on the totalweight of the concentrate.

The invention also provides a process for preparing a fuel compositionhaving improved fuel intake system-cleaning action, wherein an effectiveamount of at least one compound as defined above or of an additiveconcentrate as defined above is added to a commercial fuel composition.

Finally, the invention provides a process for preparing a lubricantcomposition having improved cleaning action, wherein an effective amountof at least one compound as defined above or of an additive concentrateas defined above is added to a commercial lubricant composition.

DETAILED DESCRIPTION OF THE INVENTION A) Preferred Embodiments ofInventive Polyamines

In the above definition of the R¹, R², R³ and R⁴ radicals, C₁-C₁₀-alkylrepresents in particular C₁-C₄-alkyl radicals such as methyl, ethyl,propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, and alsothe longer-chain pentyl, hexyl, heptyl, octyl, nonyl and decyl radicals,and also the mono- or polybranched, for example mono-, di- ortribranched, analogs thereof.

The C₄-C₆-dicarboximide ring is derived in particular frommonoethylenically unsaturated C₄-C₆-dicarboxylic acids and derivativesthereof, especially anhydrides. Suitable dicarboxylic acids are themonounsaturated forms of succinic acid, glutaric acid and adipic acid.

A1) Dicarboximide Derivatives of Group 1

These compounds are obtainable, for example, by the reaction of adicarboxylic acid substituted by a hydrophobic hydrocarbon radical or ofa dicarboxylic acid derivative substituted by a hydrophobic hydrocarbonradical with an amine which has at least one NH₂ group. Preference isgiven to reacting a carboxylic anhydride.

The molar ratio of dicarboxylic acid (derivative) groups to hydrocarbonradical is in the range of 0.8:2, or 0.9:1.5 or 0.9:1.05, as described,for example, also in EP-A-0 355 895 and 0 587 381.

The reaction of such dicarboxylic acids or derivatives thereof,especially of dicarboxylic anhydrides, with amines may result in productmixtures which comprise dicarboxylic monoamides, dicarboxylic diamides,ammonium salts of dicarboxylic monoamides, dicarboxylic monoamidemonoesters, amidines and dicarboxylic mono- and diimides. Suitable asthe inventive additive are both the acylation products specifiedindividually and mixtures thereof.

However, preference is given to dicarboximides, especially dicarboxylicmonoimides and mixtures which comprise them. The imide fraction is inparticular in the range from 1 to 100 mol %, for example from 10 to 95mol % or from 30 to 90 mol %.

The coupling ratio (PIBSA/AMINE) is in the range from 0.5 to 2 based onthe ratio of succinic acid groups to amine, for example from 0.8 to 1.2,more preferably from 0.9 to 1.05.

Amines suitable for the reaction with the dicarboxylic acid or thedicarboxylic acid derivative are polyamines of the above formula III.

Suitable polyamines are, for example, the mono-N,N-dialkyl derivativesof diethylenetriamine, triethylenetetramine, tetraethylenepentamine,pentaethylenehexamine, dipropylenetriamine, tripropylenetetramine,tetrapropylenepentamine, pentapropylenehexamine, dibutylenetriamine,tributylenetetramine, tetrabutylenepentamine, pentabutylenehexamine.

Examples include: N,N-dimethyldimethylenetriamine,N,N-diethyldimethylenetriamine, N,N-dipropyldimethylenetriamine,N,N-dimethyldiethylene-1,2-triamine, N,N-diethyldiethylene-1,2-triamine,N,N-dipropyldiethylene-1,2-triamine,N,N-dimethyldipropylene-1,3-triamine (i.e. DMAPAPA),N,N-diethyldipropylene-1,3-triamine,N,N-dipropyldipropylene-1,3-triamine,N,N-dimethyldibutylene-1,4-triamine, N,N-diethyldibutylene-1,4-triamine,N,N-dipropyldibutylene-1,4-triamine,N,N-dimethyldipentylene-1,5-triamine,N,N-diethyldipentylene-1,5-triamine,N,N-dipropyldipentylene-1,5-triamine,N,N-dimethyldihexylene-1,6-triamine, N,N-diethyldihexylene-1,6-triamineand N,N-dipropyldihexylene-1,6-triamine.

A2) Polyamines of Group 2 which are Terminated by Two Secondary and/orTertiary Amine Functions

Nonlimiting examples include:

Linear polyamines terminated by identical N,N-dialkylamino groups, suchas bis[2-(N,N-dimethylamino)ethyl]amine,bis[2-(N,N-diethylamino)ethyl]amine,bis[2-(N,N-dipropylamino)ethyl]amine,bis[3-(N,N-dimethylamino)propyl]amine,bis[3-(N,N-diethylamino)propyl]amine,bis[3-(N,N-dipropylamino)propyl]amine,bis[4-(N,N-dimethylamino)butyl]amine,bis[4-(N,N-diethylamino)butyl]amine,bis[4-(N,N-dipropylamino)butyl]amine,bis[5-(N,N-dimethylamino)pentyl]amine,bis[5-(N,N-diethylamino)pentyl]amine,bis[5-(N,N-dipropylamino)pentyl]amine,bis[6-(N,N-dimethylamino)hexyl]amine,bis[6-(N,N-diethylamino)hexyl]amine,bis[6-(N,N-dipropylamino)hexyl]amine and the corresponding analogsterminated by identical monoalkylamino groups. Also usable arecorresponding polyamines which are terminated by different mono- ordialkylamino groups, and mixtures of such compounds.

Polyamines of the above type are described in Kirk-Othmer “Encyclopediaof Chemical Technology”, 2nd edition, Volume 7, pages 22 to 37,Interscience Publishers, New York (1965, “Ethylenamines” chapter).

B) Preparation of Inventive Additives B1) Dicarboximide Additives ofGroup 1

Processes for preparing these compounds are known to those skilled inthe art. A particularly suitable process for preparingpolyalkenylsuccinimides is described in the German patent applicationDE-A-10123553.4, which is fully incorporated herein by reference. Inthis process, a polyalkenylsuccinic anhydride is reacted first with analcohol or a phenol and subsequently with an amine. Alternatively, thepolyalkenylsuccinic anhydride is reacted with the amine in the presenceof an alcohol or of a phenol.

Alcohols suitable for preparing polyalkenylsuccinimides are preferablymonohydric; however, polyhydric alcohols are also suitable.

Preference is given to using monohydric alcohols having from 1 to 16carbon atoms, such as methanol, ethanol, propanol, isopropanol, butanol,sec-butanol, isobutanol, tert-butanol, 2-hydroxymethylfuran, amylalcohol, isoamyl alcohol, vinylcarbinol, cyclohexanol, n-hexanol,6-capryl alcohol, 2-ethylhexanol, n-decanol, lauryl alcohol, isooctylalcohol and mixtures thereof. Preferred alcohols are those having from 6to 16 carbon atoms. Particular preference is given to 2-ethylhexanol.

Suitable phenols include phenol, naphthol, (o,p)-alkylphenols andsalicylic acid.

Processes for preparing polyalkenyl-substituted dicarboxylic acids orderivatives thereof are known. For instance, the German patentapplication DE-A-10123553.4 describes the preparation of apolyolefin-substituted carboxylic acid or of a derivative thereof by thereaction of a polyalkene with a monounsaturated acid or derivativethereof, in the course of which the polyalkylene adds to the double bondof the acid component in an ene reaction. Other processes are described,for example, also in WO-A-98/42808, which is incorporated herein byreference.

B2) Polyamines of Group 2 Having Two Terminal Secondary or TertiaryAmine Functions

They are prepared as described in Ullmann's Encyclopedia of IndustrialChemistry, 6^(th) ed. 2000, Electronic release, Chapt 8.2, Oligo- andPolyamines.

The polyamines of the formula III are prepared in a similar manner.

C) Different Applications of Inventive Polyamines

The inventive polyamine products can be used as additives (usually inthe form of additive packages or concentrates) for fuels, especiallydiesel fuel, heating oil, kerosene, or middle distillates in general,and gasoline fuel, or lubricants.

When the inventive polyamines are used as diesel fuel additives, theycontain an effective amount of polyamine. Appropriately, the dieselfuels contain a proportion of from about 1 to 5000 ppm, or of from about5 to 1000 ppm, for example from about 5 to 200 or from 10 to 100 ppm,based on the total weight of the diesel fuel.

The diesel fuel additive mixtures used comprise at least one furtheradditive selected from other customary detergents, corrosion inhibitors,dehazers, demulsifiers, antifoams, antioxidants, metal deactivators,multifunctional stabilizers, cetane number improvers, combustionimprovers, dyes, markers, solubilizers, antistats, lubricity improvers.

The inventive polyamines may also be used as additives for heating oil.They are used in an effective amount, appropriately in an amount of from10 to 1000 ppm, preferably from 50 to 500 ppm, based on the total weightof the heating oil. This may comprise at least one further additivewhich may be selected from corrosion inhibitors, demulsifiers,antifoams, antioxidants, metal deactivators, ferrocenes and deodorants.

The inventive polyamines may also be used as additives for gasolinefuels. These contain an effective amount of inventive polyamines,appropriately from 1 to 5000 ppm, or of from about 5 to 1000 ppm, forexample from about 5 to 200 or from 10 to 100 ppm, based on the totalweight of the gasoline fuel.

The gasoline fuel additive mixtures may also comprise at least onefurther additive selected from other customary detergent additives,carrier oils, lubricity improvers, solvents and corrosion inhibitors.

Finally, the inventive polyamines are also suitable for lubricantcompositions which contain an effective amount of inventive products,appropriately from 0.1 to 10% by weight, preferably from 0.5 to 5% byweight, based on the total weight of the lubricant composition.

The lubricant compositions may also comprise further additives which arein particular selected from lubricity improvers, wear protectionadditives, corrosion inhibitors, VI improvers.

Some additives usable as coadditives are described hereinbelow:

C1) Detergent Additives

Additives having detergent action have at least one hydrophobichydrocarbon radical having a number-average molecular weight (Mn) offrom 85 to 20 000 and at least one polar moiety selected from:

-   (a) mono- or polyamino groups having up to 6 nitrogen atoms, of    which at least one nitrogen atom has basic properties;-   (b) nitro groups, optionally in combination with hydroxyl groups;-   (c) hydroxyl groups in combination with mono- or polyamino groups,    in which at least one nitrogen atom has basic properties;-   (d) polyoxy-C₂-C₄-alkylene groups which are terminated by hydroxyl    groups, mono- or polyamino groups, in which at least one nitrogen    atom has basic properties, or by carbamate groups;-   (e) carboxylic ester groups;-   (f) moieties obtained by Mannich reaction of substituted phenols    with aldehydes and mono- or polyamines;-   (g) moieties derived from carboxylic anhydrides and having hydroxyl    and/or amino and/or amido and/or imino groups,    -   these imido-containing detergents not, like the inventive        polyamines of the formula I, having a terminal secondary or        tertiary amine group.

Additives containing mono- or polyamino groups (a) are preferablypolyalkene monoamines or polyalkene polyamines based on polypropene oron reactive (i.e. having predominantly terminal double bonds, usually inthe beta- and gamma-position) or conventional (i.e. having predominantlyinternal double bonds) polybutene or polyisobutene having M_(N)=from 300to 5000. Such additives based on reactive polyisobutene, which can beprepared from the polyisobutene which may contain up to 20% by weight ofn-butene units by hydroformylation and reductive amination with ammonia,monoamines or polyamines, such as dimethylaminopropylamine,ethylenediamine, diethylenetriamine, triethylenetetramine ortetraethylenepentamine, are disclosed in particular in EP-A 244 616.When polybutene or polyisobutene having predominantly internal doublebonds (usually in the beta and gamma position) are used as startingmaterials in the preparation of the additives, a possible preparativeroute is by chlorination and subsequent amination or by oxidation of thedouble bond with air or ozone to give the carbonyl or carboxyl compoundand subsequent amination under reductive (hydrogenating) conditions. Theamines used here for the amination may be the same as those used abovefor the reductive amination of the hydroformylated highly reactivepolyisobutene. Corresponding additives based on polypropene aredescribed in particular in WO-A 94/24231, which is fully incorporatedherein by reference.

Further preferred additives containing monoamino groups (a) are thehydrogenation products of the reaction products of polyisobutenes havingan average degree of polymerization P=from 5 to 100 with nitrogen oxidesor mixtures of nitrogen oxides and oxygen, as described in particular inWO-A 97/03946, which is fully incorporated herein by reference.

Further preferred additives containing monoamino groups (a) are thecompounds obtainable from polyisobutene epoxides by reaction with aminesand subsequent dehydration and reduction of the amino alcohols, asdescribed in particular in DE-A 196 20 262, which is fully incorporatedherein by reference.

Additives containing nitro groups, optionally in combination withhydroxyl groups, (b) are preferably reaction products of polyisobuteneshaving an average degree of polymerization P=from 5 to 100 or from 10 to100 with nitrogen oxides or mixtures of nitrogen oxides and oxygen, asdescribed in particular in WO-A 96/03367 and WO-A 96/03479, which arefully incorporated herein by reference. These reaction products aregenerally mixtures of pure nitropolyisobutenes (e.g.alpha,beta-dinitropolyisobutene) and mixed hydroxynitropolyisobutenes(e.g. alpha-nitro-beta-hydroxypolyisobutene).

Additives containing hydroxyl groups, optionally in combination withmono- or polyamino groups, (c) are in particular reaction products ofpolyisobutene epoxides obtainable from polyisobutene having preferablypredominantly terminal double bonds and M_(N)=from 300 to 5000, withammonia or mono- or polyamines, as described in particular in EP-A 476485, which is fully incorporated herein by reference.

Additives containing polyoxy-C₂- to C₄-alkylene moieties (d) arepreferably polyethers or polyetheramines which are obtainable byreaction of C₂- to C₆₀-alkanols, C₆- to C₃₀-alkanediols, mono- ordi-C₂-C₃₀-alkylamines, C₁-C₃₀-alkylcyclohexanols or C₁-C₃₀-alkylphenolswith from 1 to 30 mol of ethylene oxide and/or propylene oxide and/orbutylene oxide per hydroxyl group or amino group and, in the case of thepolyetheramines, by subsequent reductive amination with ammonia,monoamines or polyamines. Such products are described in particular inEP-A 310 875, EP-A 356 725, EP-A 700 985 and U.S. Pat. No. 4,877,416,which are fully incorporated herein by reference. In the case ofpolyethers, such products also have carrier oil properties. Typicalexamples of these are tridecanol butoxylates, isotridecanol butoxylates,isononylphenol butoxylates and polyisobutenol butoxylates andpropoxylates and also the corresponding reaction products with ammonia.

Additives containing carboxylic ester groups (e) are preferably estersof mono-, di- or tricarboxylic acids with long-chain alkanols orpolyols, in particular those having a minimum viscosity of 2 mm² at 100°C., as described in particular in DE-A 38 38 918, which is fullyincorporated herein by reference. The mono-, di- or tricarboxylic acidsused may be aliphatic or aromatic acids, and particularly suitable esteralcohols or ester polyols are long-chain representatives having, forexample, from 6 to 24 carbon atoms. Typical representatives of theesters are adipates, phthalates, isophthalates, terephthalates andtrimellitates of isooctanol, of isononanol, of isodecanol and ofisotridecanol. Such products also have carrier oil properties.

Additives containing moieties conventional obtained by conventionalMannich reaction of phenolic hydroxyl groups with aldehydes and mono- orpolyamines (f) are preferably reaction products ofpolyisobutene-substituted phenols with formaldehyde and primary mono- orpolyamines such as ethylenediamine, diethylenetriamine,triethylenetetramine, tetraethylenepentamine ordimethylaminopropylamine. The polyisobutenyl-substituted phenols maystem from conventional or highly reactive polyisobutene having Mn=from300 to 5 000. Such “polyisobutene-Mannich bases” are described inparticular in EP-A 831 141, which is fully incorporated herein byreference.

Additives containing moieties derived from carboxylic anhydrides andhaving hydroxyl and/or amino and/or amido and/or imido groups (g) arepreferably corresponding derivatives of dicarboxylic anhydrides, morepreferably of succinide anhydride. It is self-evident that the term“moieties derived from carboxylic anhydrides . . . .” does notnecessarily require that the starting materials actually have to be thecarboxylic anhydrides. It will be appreciated that such moieties mayalso be obtained by the reaction of other carboxylic acid derivativeswhich have the required activity, for example carbonyl halides, or elseby the reaction of the carboxylic acid itself when suitable activationmeasures are taken. However, carboxylic anhydrides are particularlysuitable derivatives for the conversion to the moieties mentioned.

The polar moiety of component A is more preferably a moiety derived fromcarboxylic anhydrides and having hydroxyl and/or amino and/or amidoand/or imido groups (g), especially having amido and/or imido groups,i.e. N-acyl moieties.

The hydrophobic hydrocarbon radical of the above-described detergentadditives (a) to (g) and the hydrophobic R radical of inventivepolyamine detergents of the formulae I and II are preferably a homo- orcopolymer radical whose repeating units are derived from monomers whichare selected from propene, n-butene and isobutene and mixtures thereof.

The homo- or copolymer radicals is more preferably a polyisobuteneradical. In particular, the homo- or copolymer radical is a radicalwhich is derived from “reactive” polyisobutenes which differ from the“low-reactivity” polyisobutenes by the content of terminal double bonds.Reactive polyisobutenes differ from low-reactivity polyisobutenes inthat they contain at least 50 mol %, preferably at least 60 mol % andmore preferably at least 80 mol %, based on the total number ofpolyisobutene macromolecules, of terminal double bonds. The terminaldouble bonds may be either vinyl double bonds [—CH═C(CH₃)₂] orvinylidene double bonds [—CH₂—C(═CH₂)—CH₃]. Preference is given inparticular to polyisobutenes which have uniform polymer skeletons.Uniform polymer skeletons are in particular those polyisobutenes whichare composed to an extent of at least 85% by weight, preferably to anextent of at least 90% by weight and more preferably to an extent of atleast 95% by weight, of isobutene units. For example, such reactivepolyisobutenes have a number-average molecular weight in the range from100 to 20 000. Suitable reactive polyisobutenes for preparing fueladditives are in particular those which have a number-average molecularweight in the range from 100 to 3000, such as from 200 to 2500 or from500 to 1500, for example a number-average molecular weight of about 550,about 800 or about 1000.

Suitable reactive polyisobutenes for preparing lubricant additives arein particular those which have a number-average molecular weight in therange from 1000 to 15 000, more preferably from 1300 to 12 500 and mostpreferably from 2000 to 10 000, for example a number-average molecularweight of about 1500, about 2000 or about 2300.

The reactive polyisobutenes preferably additionally have apolydispersity of less than 3.0, in particular less than 1.9 and morepreferably of less than 1.7 or less than 1.5. Polydispersity refers tothe quotient of weight-average molecular weight M_(W) divided by thenumber-average molecular weight M_(N).

Particularly suitable reactive polyisobutenes are, for example, theGlissopal brands of BASF AG, in particular Glissopal 1000 (M_(N)=1000)and Glissopal V 33 (M_(N)=550) and Glissopal 2300 (M_(N)=2300) andmixtures thereof. Other number-average molecular weights may be attainedby a manner known in principle, by mixing polyisobutenes of differentnumber-average molecular weights or by extractively enrichingpolyisobutenes of certain molecular weight ranges.

C2) Cold Flow Improvers

The additives improving cold properties (cold flow improvers) includemiddle distillate flow improvers (“MDFIs”), paraffin dispersants(“WASAs”) and the combination of the two additives (“WAFIs”).

The suitable cold flow improvers include in particular the followingactive substance groups, as described, for example, in WO 95/33805:

-   aa) copolymers of ethylene with at least one further ethylenically    unsaturated monomer which are different from the polymers used in    accordance with the invention;-   ab) comb polymers;-   ac) polyoxyalkylenes;-   ad) polar nitrogen compounds;-   ae) sulfo carboxylic acids or sulfonic acids or their derivatives;    and-   af) poly(meth)acrylic esters.

In the case of copolymers of ethylene with at least one furtherethylenically unsaturated monomer (aa) the monomer is preferablyselected from alkenylcarboxylic esters, (meth)acrylic esters andolefins.

Examples of suitable olefins are those having from 3 to 10 carbon atoms,and having from 1 to 3, preferably having 1 or 2, carbon-carbon doublebonds, in particular having one carbon-carbon double bond. In the lattercase, the carbon-carbon double bond may either be terminal (a-olefin) orinternal. However, preference is given to α-olefins, more preferablyα-olefins having from 3 to 6 carbon atoms, such as propene, 1-butene,1-pentene and 1-hexene.

Examples of suitable (meth)acrylic esters are esters of (meth)acrylicacid with C₁-C₁₀-alkanols, in particular with methanol, ethanol,propanol, isopropanol, n-butanol, sec-butanol, isobutanol, tert-butanol,pentanol, hexanol, heptanol, octanol, 2-ethylhexanol, nonanol anddecanol.

Examples of suitable alkenylcarboxylic esters are the vinyl and propenylesters of carboxylic acids having from 2 to 20 carbon atoms whosehydrocarbon radical may be linear or branched. Among these, preferenceis given to the vinyl esters. Among the carboxylic acids having branchedhydrocarbon radicals, preference is given to those whose branch is inthe α-position to the carboxyl group, and particular preference is givento the α-carbon atom being tertiary, i.e. to the carboxylic acid being aneocarboxylic acid. However, preference is given to the hydrocarbonradical of the carboxylic acid being linear.

Examples of suitable alkenylcarboxylic esters are vinyl acetate, vinylpropionate, vinyl butyrate, vinyl-2-ethylhexanoate, vinyl neopentanoate,vinyl hexanoate, vinyl neononanoate, vinyl neodecanoate and thecorresponding propenyl esters, although preference is given to the vinylesters. A particularly preferred alkenylcarboxylic ester is vinylacetate.

Particular preference is given to selecting the ethylenicallyunsaturated monomer from alkenylcarboxylic esters.

Copolymers which contain two or more differing copolymerizedalkenylcarboxylic esters are also suitable, and these differ in thealkenyl function and/or in the carboxylic group. Copolymers which, inaddition to the alkenylcarboxylic ester(s), contain at least onecopolymerized olefin and/or at least one copolymerized (meth)acrylicester are likewise suitable.

The ethylenically unsaturated monomer is copolymerized in the copolymerin an amount of preferably from 1 to 50 mol %, more preferably from 10to 50 mol % and in particular from 5 to 20 mol %, based on the entirecopolymer.

The copolymer (aa) preferably has a number-average molecular weightM_(n) of from 1000 to 20 000, more preferably from 1000 to 10 000 and inparticular from 1000 to 6000.

Examples of comb polymers (ab) are those described in “Comb-LikePolymers. Structure and Properties”, N. A. Platé and V. P. Shibaev, J.Poly. Sci. Macromolecular Revs. 8, pages 117 to 253 (1974). Among thosedescribed there, examples of suitable comb polymers are those of theformula II

where

D is R¹⁷, COOR¹⁷, OCOR¹⁷, R¹⁸, COOR¹⁷ or OR¹⁷, E is H, CH₃, D or R¹⁸, Gis H or D,

J is H, R¹⁸, R¹⁸COOR¹⁷, aryl or heterocyclyl,

K is H, COOR¹⁸, OCOR¹⁸, OR¹⁸ or COOH,

L is H, R¹⁸, COOR¹⁸, OCOR¹⁸, COOH or aryl,where

-   -   R¹⁷ is a hydrocarbon radical having at least 10 carbon atoms,        preferably having from 10 to 30 carbon atoms,    -   R¹⁸ is a hydrocarbon radical having at least one carbon atom,        preferably having from 1 to 30 carbon atoms,        m is a molar fraction in the range from 1.0 to 0.4 and        n is a molar fraction in the range from 0 to 0.6.

Preferred comb polymers are obtainable, for example, by copolymerizingmaleic anhydride or fumaric acid with another ethylenically unsaturatedmonomer, for example with an α-olefin or an unsaturated ester such asvinyl acetate, and then esterifying the anhydride or acid function withan alcohol having at least 10 carbon atoms. Further preferred combpolymers are copolymers of α-olefins and esterified comonomers, forexample esterified copolymers of styrene and maleic anhydride oresterified copolymers of styrene and fumaric acid. Mixtures of combpolymers are also suitable. Comb polymers may also be polyfumarates orpolymaleates. Homo- and copolymers of vinyl ethers are also suitablecomb polymers.

Examples of suitable polyoxyalkylenes (ac) are polyoxyalkylene esters,ethers, ester/ethers and mixtures thereof. The polyoxyalkylene compoundspreferably contain at least one linear alkyl group, more preferably atleast two linear alkyl groups, having from 10 to 30 carbon atoms and apolyoxyalkylene group having a molecular weight of up to 5000. The alkylgroup of the polyoxyalkylene radical preferably contains from 1 to 4carbon atoms. Such polyoxyalkylene compounds are described, for example,in EP-A-0 061 895 and also in U.S. Pat. No. 4,491,455, which are fullyincorporated herein by way of reference. Preferred polyoxyalkyleneesters, ethers and ester/ethers have the general formula III

R¹⁹[O—(CH₂)_(y)]_(x)O—R²⁰  (III)

whereR¹⁹ and R²⁰ are each independently R²¹, R²¹⁻CO—, R²¹—O—CO(CH₂)_(z)— orR²¹—O—CO(CH₂)_(z)—CO—, where R²¹ is linear C₁-C₃₀-alkyl,y is a number from 1 to 4,x is a number from 2 to 200, andz is a number from 1 to 4.

Preferred polyoxyalkylene compounds of the formula III in which both R¹⁹and R²⁰ are R²¹ are polyethylene glycols and polypropylene glycolshaving a number-average molecular weight of from 100 to 5000. Preferredpolyoxyalkylenes of the formula III in which one of the R¹⁹ radicals isR²¹ and the other is R²¹⁻CO— are polyoxyalkylene esters of fatty acidshaving from 10 to 30 carbon atoms, such as stearic acid or behenic acid.Preferred polyoxyalkylene compounds in which both R¹⁹ and R²⁰ are anR²¹—CO— radical are diesters of fatty acids having from 10 to 30 carbonatoms, preferably of stearic or behenic acid.

The polar nitrogen compounds (ad) which are appropriately oil-solublemay be either ionic or nonionic and preferably have at least one, morepreferably at least two, substituents of the formula >NR²² where R²² isa C₈-C₄₀-hydrocarbon radical. The nitrogen substituents may also be inquaternized form, i.e. in cationic form. Examples of such nitrogencompounds include ammonium salts and/or amides which are obtainable byreacting at least one amine substituted by at least one hydrocarbonradical with a carboxylic acid having from 1 to 4 carboxyl groups orwith a suitable derivative thereof. The amines preferably contain atleast one linear C₈-C₄₀-alkyl radical. Examples of suitable primaryamines include octylamine, nonylamine, decylamine, undecylamine,dodecylamine, tetradecylamine and the higher linear homologs. Examplesof suitable secondary amines include dioctadecylamine andmethylbehenylamine. Amine mixtures, in particular amine mixturesobtainable on the industrial scale, such as fatty amines or hydrogenatedtallamines, are also suitable, as described, for example, in UllmannsEncyclopedia of Industrial Chemistry, 6th edition, 2000 electronicrelease, Chapter “Amines, aliphatic”. Examples of acids suitable for thereaction include cyclohexane-1,2-dicarboxylic acid,cyclohexene-1,2-dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid,naphthalenedicarboxylic acid, phthalic acid, isophthalic acid,terephthalic acid and succinic acids substituted by long-chainhydrocarbon radicals.

Further examples of polar nitrogen compounds are ring systems which bearat least two substituents of the formula -A-NR²³R²⁴ where A is a linearor branched aliphatic hydrocarbon group which is optionally interruptedby one or more groups selected from O, S, NR³⁵ and CO, and R²³ and R²⁴are each C₉-C₄₀-hydrocarbon radicals which are optionally interrupted byone or more groups selected from O, S, NR³⁵ and CO, and/or substitutedby one or more substituents selected from OH, SH and NR³⁵R³⁶ where R³⁵is C₁-C₄₀-alkyl which is optionally interrupted by one or more moietieswhich are selected from CO, NR³⁵, O and S, and/or substituted by one ormore radicals selected from NR³⁷R³⁸, OR³⁷, SR³⁷, COR³⁷, COOR³⁷,CONR³⁷R³⁸, aryl or heterocyclyl, where R³⁷ and R³⁸ are eachindependently selected from H or C₁-C₄-alkyl; and R³⁶ is H or R³⁵.

A is preferably a methylene or polymethylene group having from 2 to 20methylene units. Examples of suitable R²³ and R²⁴ radicals include2-hydroxyethyl, 3-hydroxypropyl, 4-hydroxybutyl, 2-ketopropyl,ethoxyethyl and propoxypropyl. The cyclic system may be a homocyclic,heterocyclic, fused polycyclic or nonfused polycyclic system. The ringsystem is preferably carbo- or heteroaromatic, in particularcarboaromatic. Examples of such polycyclic ring systems include fusedbenzoid structures such as naphthalene, anthracene, phenanthrene andpyrene, fused nonbenzoid structures such as azulene, indene, hydrindeneand fluorene, nonfused polycycles such as diphenyl, heterocycles such asquinoline, indole, dihydroindole, benzofuran, coumarin, isocoumarin,benzthiophene, carbazole, diphenylene oxide and diphenylene sulfide,nonaromatic or partially saturated ring systems such as decalin, andthree-dimensional structures such as α-pinene, camphene, bornylene,norbonane, norbonene, bicyclooctane and bicyclooctene.

Further examples of suitable polar nitrogen compounds are condensates oflong-chain primary or secondary amines with carboxyl-containingpolymers.

The polar nitrogen compounds specified hereinabove are described in WO00/44857 and also in the references mentioned therein, which are fullyincorporated herein by way of reference.

Suitable polar nitrogen compounds are also described in, for example,DE-A-198 48 621, DE-A-196 22 052 and EP-B-398 101, which areincorporated herein by way of reference.

Examples of suitable sulfo carboxylic acids/sulfonic acids and theirderivatives (ae) are those of the general formula IV

whereY is SO₃ ⁻(NR²⁵ ₃R²⁶)⁺, SO₃ ⁻(NHR²⁵ ₂R²⁶)⁺, SO₃ ⁻(NH₂R²⁵R²⁶), SO₃⁻(NH₃R²⁶) or SO₂NR²⁵R²⁶,X is Y, CONR²⁵R²⁷, CO₂ ⁻(NR²⁵ ₃R²⁷)⁺, CO₂ ⁻(NHR²⁵ ₂R²⁷)⁺, R²⁸—COOR²⁷,NR²⁵COR²⁷, R²⁸OR²⁷, R²⁸OCOR²⁷, R²⁸R²⁷, N(COR²⁵)R²⁷ or Z⁻(NR²⁵ ₃R²⁷)⁺,

-   -   where    -   R²⁵ is a hydrocarbon radical,    -   R²⁶ and R²⁷ are each alkyl, alkoxyalkyl or polyalkoxyalkyl        having at least 10 carbon atoms in the main chain,    -   R²⁸ is C₂-C₅-alkylene,        Z⁻ is one anion equivalent and        A and B are each alkyl, alkenyl or two substituted hydrocarbon        radicals, or, together with the carbon atom to which they are        bonded, form an aromatic or cycloaliphatic ring system.

Such sulfo carboxylic acids and sulfonic acids and their derivatives aredescribed in EP-A-0 261 957, which is fully incorporated herein by wayof reference.

Suitable poly(meth)acrylic esters (af) are both homo- and copolymers ofacrylic and methacrylic esters. Preference is given to acrylicester/homopolymers derived from C₁-C₄₀ alcohols. Preference is alsogiven to copolymers of at least two differing (meth)acrylic esters whichdiffer in respect of the esterified alcohol. The copolymer may alsocontain a further, different copolymerized olefinically unsaturatedmonomer. The weight-average molecular weight of the polymer ispreferably from 50 000 to 500 000. A particularly preferred polymer is acopolymer of methacrylic acid and methacrylic esters of saturated C₁₄-and C₁₅-alcohols in which the acid groups are neutralized byhydrogenated tallamine. Suitable poly(meth)acrylic esters are described,for example, in WO 00/44857 which is fully incorporated herein by way ofreference.

C2) Lubricity Improvers

The customary lubricity improvers include, for example, carboxylicacids, especially fatty acids, esters thereof, especially with polyols,mixtures of these acids and esters, ashlessly burning N-acyl compoundssuch as polyalkenylsuccinamides, mixtures of the acids and/or estersmentioned with these N-acyl compounds, as described, for example, in WO96/23855, bis(hydroxyalkyl) fatty amines or hydroxyacetamides.

C3) Diluents

Inventive additives are frequently formulated together with solvents ordiluents. Suitable diluents are, for example, the fractions obtained incrude oil processing, such as kerosene, naphtha or brightstock.Additionally suitable are aromatic and aliphatic hydrocarbons andalkoxyalkanols. Diluents used with preference for middle distillates,especially for diesel fuels, are naphtha, kerosene, diesel fuels,aromatic hydrocarbons such as Solvent Naphtha heavy, Solvesso® orShellsol® and mixtures of these solvents and diluents.

D) Fuels and Lubricants

Fuels which are additized preferably in accordance with the inventionare gasoline fuels and middle distillates such as diesel fuel, heatingoil or kerosene, of which particular preference is given to diesel fuel.

The diesel fuels are, for example, mineral oil raffinates whichtypically have a boiling range of from 100 to 400° C. These are usuallydistillates having a 95% point up to 360° C. or even higher. These mayalso be “Ultra Low Sulphur Diesel” or “City Diesel”, characterized by amaximum 95% point of, for example, 345° C. and a maximum sulfur contentof 0.005% by weight, or by a 95% point of, for example, 285° C. and amaximum sulfur content of 0.001% by weight. Suitable in addition to thediesel fuels obtainable by refining are those which are obtainable bycoal gasification or gas liquefaction (“gas-to-liquid” (GTL) fuels).Also suitable are mixtures of the aforementioned diesel fuels withrenewable fuels such as biodiesel or bioethanol.

Particular preference is given to using the inventive additive foradditizing diesel fuels having a low sulfur content, i.e. having asulfur content of less than 0.05% by weight, preferably of less than0.02% by weight, in particular of less than 0.005% by weight andespecially of less than 0.001% by weight of sulfur.

The examples which follow illustrate the invention but withoutrestricting it.

EXAMPLES Preparation Example 1 Preparation of aPolyisobutenylsuccinimide of the Formula II

(R³,R⁴=methyl, x,z=3, y=1, R=polyisobutylene, Mn=550)

A four-neck flask equipped with nitrogen tap, internal contactthermosensor and distillation head with condenser is initially chargedunder nitrogen with a mixture of polyisobutenylsuccinic anhydride(PIBSA) (polyisobutenyl chain having Mn=550) in 2-ethylhexanol at 140°C. With vigorous stirring, N,N-dimethyldipropylenetriamine (DMAPAPA) israpidly added dropwise. The molar ratio of PIBSA to amine used is 1:1.05(succinic acid groups: amine). An exothermic reaction is observed with atemperature rise to 151° C. Subsequently, the reaction mixture is heatedto 170° C. and stirred under nitrogen for 2.5 hours. Application of avacuum of 500 mbar for 30 minutes then removes the alcohol present.Finally, the mixture is diluted to a 50% solution using Solvesso® 150.

Preparation Example 2 Preparation of a Polyisobutenylsuccinimide of theFormula II

(R³,R⁴=methyl, x,z=3, y=1, R=polyisobutenyl, Mn=1000)

The procedure of Example 1 is repeated, except that the correspondingmolar amount of PIBSA 1000 (polyisobutenyl chain having Mn=1000) is usedinstead of PIBSA 550.

Use Example Determination of the Detergent Activity of InventivePolyamines

The detergency of inventive polyamines in comparison to a commercialdetergent additive was determined in a standardized test engine XUD9(Peugeot engine) using the CEC F23 A 01 test method. In this test, thedegree of carbonization of the nozzles was determined in the injectionnozzle via the restriction of an air flow at needle stroke 0.1 mm. 100%flow restriction means full carbonization; 0% means no carbonization.

The following fuels were used:

-   -   Halternann RF 93    -   Diesel fuel to EN 590 (S content<50 ppm)    -   Diesel fuel to EN 590 (S content<10 ppm)

The following additives having detergent action were used:

-   -   Kerocom PIBSI: polyisobutenesuccinimide obtainable by reacting        polyisobutenesuccinic anhydride (polyisobutenyl chain having        Mn=1000) and tetraethylenepentamine in a molar ratio of 1:1.05        (succinic acid to amine)    -   PIBSI I: according to Preparation Example 1    -   PIBSI II: according to Preparation Example 2    -   Polyamine: bis[3-(N,N-dimethylamino)propyl]amine (compound of        the formula I where R¹, R², R³, R⁴=methyl, x, z=3 and y=1)

For all PIBSIs used, PIBSAs having a comparable degree of succinylationwere used.

These additives were examined in the above-specified tests for theirdetergent action at different dosage in different diesel fuels. Thepercentage flow restriction values determined are compiled in thefollowing Table 1:

Flow Restriction Detergent Dosage [ppm] Fuel [%] Kerocom PIBSI 52 RF 9375 (comparison) 70 EN 590 S < 50 ppm 68 66 EN 590 S < 10 ppm 67 PIBSI I30 RF 93 37 PIBSI II 30 RF 93 7 15 RF 93 37 15 EN 590 S < 10 ppm 61 15EN 590 S < 50 ppm 61 Polyamine 15 RF 93 56

Relative to the comparative substance used, the inventive additivesexhibit distinctly better detergent activity at simultaneously lowerdosage.

1-18. (canceled)
 19. A method for reducing carbonization of nozzles indiesel engines comprising adding a detergent additive to fuel whereinthe detergent additive is a compound of the general formula (I):R¹R²N((CH₂)_(x)NH)_(y)(CH₂)_(z)NR³R⁴  (I) where R¹ and R² are eachindependently H or C₁-C₁₀-alkyl but neither R¹ and R² are simultaneouslyH; or R¹ and R² together with the nitrogen atom to which they are bondedform a C₄-C₆-dicarboximide ring which is substituted by at least onepolyalkenyl radical which has a number-average molecular weight Mn offrom 100 to 2500; R³ and R⁴ are independently C₁-C₁₀-alkyl; y is aninteger from 1 to 100 and x and z are independently an integer from 2 to12.
 20. The method according to claim 19, wherein the detergent additiveof the formula I is added in an amount which brings about a maximumdegree of carbonization of 80% determined to CEC F23 A 01 (in an XUD9test engine at needle stroke 0.1 mm) via the percentage in air flowrestriction.
 21. The method according to claim 20, wherein the degree ofcarbonization is 0 to 65%.
 22. The method according to claim 19, whereinthe compound has the following general formula II

where R is a polyalkenyl radical which has a number-average molecularweight Mn of from 100 to
 2500. 23. The method according to claim 22,wherein R is a polyisobutenyl radical.
 24. The method according to claim23, wherein the polyisobutenyl radical has an Mn of from about 500 to1000.
 25. The method according to claim 19, wherein x and z are eachindependently an integer from 2 to 4 and y is 1, 2 or
 3. 26. The methodaccording to claim 19, wherein R³ and R⁴ are each independentlyC₁-C₄-alkyl.
 27. The method according to claim 19, wherein R¹, R², R³and R⁴ are each independently C₁-C₄-alkyl.
 28. The method according toclaim 19, wherein the compound is an imide of the formula I obtainableby reacting a cyclic C₄-C₆-dicarboxylic anhydride which is substitutedby at least one polyalkylene radical which has a number-averagemolecular weight Mn of from 100 to 2500 with a polyamine of the formulaIIIH₂N((CH₂)_(x)NH)_(y)(CH₂)_(z)NR³R⁴  (III) and optionally removingvolatile constituents of the reaction mixture.
 29. The method accordingto claim 28, wherein said imide is at least one compound of the formulaII:

where R is a polyalkenyl radical which has a number-average molecularweight Mn of from 100 to
 2500. 30. The method according to claim 19,wherein at least one further conventional additive selected from thegroup consisting of detergent additives, carrier oils, corrosioninhibitors, frictional wear-reducing additives, cetane number improvers,demulsifiers, antifoams, solvents, solubilizers, antioxidants, metaldeactivators, deodorants and cold flow improvers other than compounds ofthe formula I, and mixtures comprising one or more of these additives iscombined with the compound of general formula I.
 31. A fuel compositioncomprising, in a majority of a hydrocarbon fuel boiling in the rangefrom 100 to 500° C., an effective amount of at least one detergentadditive of the formula I:R¹R²N((CH₂)_(x)NH)_(y)(CH₂)_(z)NR³R⁴  (I) where R¹ and R² are eachindependently H or C₁-C₁₀-alkyl but neither R¹ and R² are simultaneouslyH; or R¹ and R² together with the nitrogen atom to which they are bondedform a C₄-C₆-dicarboximide ring which is substituted by at least onepolyalkenyl radical which has a number-average molecular weight Mn offrom 100 to 2500; R³ and R⁴ are independently C₁-C₁₀-alkyl; y is aninteger from 1 to 100 and x and z are independently an integer from 2 to12.
 32. The method according to claim 19, wherein the fuel comprises amiddle distillate fuel.
 33. A lubricant composition comprising, in acustomary lubricant, at least an effective amount of at least onedetergent additive of the formula I:R¹R²N((CH₂)_(x)NH)_(y)(CH₂)_(z)NR³R⁴  (I) where R¹ and R² are eachindependently H or C₁-C₁₀-alkyl but neither R¹ and R² are simultaneouslyH; or R¹ and R² together with the nitrogen atom to which they are bondedform a C₄-C₆-dicarboximide ring which is substituted by at least onepolyalkenyl radical which has a number-average molecular weight Mn offrom 100 to 2500; R³ and R⁴ are independently C₁-C₁₀-alkyl; y is aninteger from 1 to 100 and x and z are independently an integer from 2 to12.
 34. An additive concentrate comprising at least one detergentadditive of the formula I:R¹R²N((CH₂)_(x)NH)_(y)(CH₂)_(z)NR³R⁴  (I) where R¹ and R² are eachindependently H or C₁-C₁₀-alkyl but neither R¹ and R² are simultaneouslyH; or R¹ and R² together with the nitrogen atom to which they are bondedform a C₄-C₆-dicarboximide ring which is substituted by at least onepolyalkenyl radical which has a number-average molecular weight Mn offrom 100 to 2500; R³ and R⁴ are independently C₁-C₁₀-alkyl; y is aninteger from 1 to 100 and x and z are independently an integer from 2 to12, in combination with at least one further customary fuel or lubricantadditive.
 35. A process for preparing a diesel fuel composition foreffecting a reduction of nozzle carbonization, comprising adding to acommercial diesel fuel composition an effective amount of at least onecompound of the formula I:R¹R²N((CH₂)_(x)NH)_(y)(CH₂)_(z)NR³R⁴  (I) where R¹ and R² are eachindependently H or C₁-C₁₀-alkyl but neither R¹ and R² are simultaneouslyH; or R¹ and R² together with the nitrogen atom to which they are bondedform a C₄-C₆-dicarboximide ring which is substituted by at least onepolyalkenyl radical which has a number-average molecular weight Mn offrom 100 to 2500; R³ and R⁴ are independently C₁-C₁₀-alkyl; y is aninteger from 1 to 100 and x and z are independently an integer from 2 to12.
 36. A process for preparing a diesel fuel composition for effectinga reduction of nozzle carbonization comprising adding to a commercialdiesel fuel composition an effective amount of the additive concentrateaccording to claim
 34. 37. The method according to claim 19, wherein thedetergent additive is present in an amount of about 1 to 200 mg/kg offuel.
 38. The method according to claim 19, wherein the detergentadditive is present in an amount of about 2 to 16 mg/kg of fuel.